کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
295117 511525 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Frequency dependent directivity of periodic permanent magnet electromagnetic acoustic transducers
ترجمه فارسی عنوان
هدایت وابسته به فرکانس مبدل های الکترومغناطیسی دائمی
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی عمران و سازه
چکیده انگلیسی


• Directivity modelling of frequency steered arrays.
• Pulsed array generates wavefront with varying frequency.
• Frequency dependent directivity means ultrasound can be steered with single signal.

Beam steering has been achieved using shear horizontal waves generated using a periodic permanent magnet (PPM) electromagnetic transducer (EMAT). Unlike phased arrays, where steering is achieved by carefully controlling the firing of individual elements, the spatial periodicity of the PPM EMAT is ultilised to steer the beam whilst exciting all elements simultaneously. Due to the periodic nature of the array, the interference of individual waves from each of the elements creates a highly frequency dependent angle of propagation, allowing the directivity to be changed by simply varying the frequency of the input signal. Simultaneous excitation precludes the need for complicated and expensive phased array hardware. A frequency domain model is developed so that the beam characteristics, such as steering angle and beam width, can be calculated, allowing for investigation into the beam steering qualities of the PPM transducer. Broadband pulsed generation is also demonstrated, showing how a wave is generated over a large range of angles, meaning a large area can be covered with a single pulse. Interesting properties of this wave, such as a variation of frequency as a function of angle, and how this can be useful, are also discussed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: NDT & E International - Volume 62, March 2014, Pages 137–143
نویسندگان
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